This invention relates to a method and apparatus for winding coreless rolls or logs and, more particularly, relating to the transfer of a web to a winding mandrel for developing a coreless log. A "log" has the same diameter as the commercial sized roll of bathroom tissue or kitchen toweling but is much longer. Current practice is to transversely cut the log into rolls, viz., in the U.S. 41/2" long for bathroom tissue and 11" long for kitchen toweling while in Europe the counterpart lengths are 140 mm and 280 mm, respectively.
A few coreless wound products have been in existence for the last 10 or 15 years. These can be separated into three categories. First, there is the large diameter tissue and towel rolls made to dispense from the center. Second, there are tissue rolls with very small "core" diameters made to dispense either from special, barbed shafts or without the use of any dispensing shaft but rather using a cradle. The use of these two categories has been generally confined to Europe. Third, there is a category which is frequently discussed but has never caught on. Exemplary of this is a bathroom tissue roll for a standard home dispenser but without the core. One of the obstacles in developing such a product is the difficulty in starting the wind.
The invention contemplates winding a web in convolute fashion on a "bare" mandrel by using a novel arrangement of an enveloping roller, means for severing a web equipped with transverse perforations and means for directing the leading edge portion of the severed web into a nip between the enveloping roller and a "new" mandrel so as to obtain a "glue-less" transfer.
Representative of the prior art is co-owned U.S. Pat. No. 3,697,010 and machines made according to the patent teachings were not made for nor suited for cross perforated tissue and/or kitchen toweling. A prior art commercial machine made by the assignor hereof Paper Converting Machine Company, of Green Bay, Wis. and sold in Europe produced coreless rolls but not with commercially-acceptable perforations. The machine used orbiting mandrels with a stationary anvil positioned within the mandrel orbit. A rotating enveloping roller moved through the web path to move the web into partial wrapping engagement with the mandrel next to be wound--this from the upstream side of the mandrel. A second rotating "cutoff" roller containing a protruding knife and an air jet moved against the web downstream of the mandrel to complete the wrap. The cyclic impact of the protruding knife caused the web to pulsate and the normal bonds between adjacent, aligned perforations (viz., the uncut web) were unable to avoid rupture due to this pulsation and prior to knife engagement with the anvil. As a consequence, commercial bathroom and toweling with bonds of the order of 1/2-1 mm could not be reliably produced--because the pulsation caused the web to rupture prematurely and thus prevent the achievement of the mandatory exact "count".
This drawback has been solved by the instant invention where, after the enveloping roller has achieved partial wrap of the "new" mandrel, a steady, pulsation-less force applying means is provided in the place of the cutoff roller for a web having longitudinally spaced lines of perforation with the perforations in each line being separated by bonds of the order of 1/2-1 mm. This achieves the goal of having the web severed along a predetermined line of perforation to achieve the exact count.
Other objects and advantages of the invention may be seen in the details of construction and operation set forth in the ensuing specification.